A high-lift aid is a device on an aerofoil of an aircraft that is used to increase the lift coefficient of the aerofoils in certain situations, as a result of which the aircraft can fly at relatively low speeds. The high-lift aid additionally provides an increase in drag required during the landing and take-off phases.
High-lift systems comprise high-lift flaps that are arranged on the wing of the aircraft that can be moved between a retracted position and a plurality of extended positions by means of an actuator. When the flap is extended, the flap is moved backwards with respect to the wing and thus the active wing profile is lengthened. The profile curvature increases, the angle of incidence of the flap becomes larger and the associated increase in the aerodynamic lift occurs. Air flows from the lower face of the wing to the upper face of the flap at high speed through the gap formed between the flap and wing during the extension movement, further contributing to the lift increase.
One of the most common types of high-lift system is the Fowler flap, in which, while the flap is being extended, it is moved backwards away from the wing, forming the above-mentioned gap. In particular as the flap is increasingly extended, this movement is accompanied by an increase in the angle of incidence of the flap.
A mechanism for actuating a Fowler flap typically contains, on the underside of the wing, a rail (track) which extends obliquely downwards from the wing towards the rear and on which a carriage is displaceably mounted. The carriage is coupled to the flap by means of a joint.
The carriage is conventionally mounted on the track by means of rolling bearings or barrel roller bearings. During operation, these often have to be lubricated and require a large amount of installation space. During use, the rollers can become blocked, which can lead to the rollers flattening in some places. The tracks can also become damaged as a result, which in turn necessitates laborious repairs.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.